Arsaces Xxv. or CHOSROES
CHOSROES, called by Dio Cassius OSROES, a younger son of Vologeses I., succeeded his brother Pacorus during the reign of Trajan. Soon after his accession, he invaded Armenia, expelled Exedares, the son of Tiridates, who had been appointed king by the Romans, and gave the crown to his nephew Parthamasiris, the son of his brother Pacorus. Trajan hastened in person to the east, conquered Armenia, and reduced it to the form of a Roman province. Parthamasiris also fell into his hands.
After concluding peace with Augarus, the ruler of Edessa, Trajan overran the northern part of Mesopotamia, took Nisibis land several other cities, and, after a most glorious campaign, returned to Antioch to winter, A. D. 114.
In consequence of these successes, he received the surname of Parthicus
from the soldiers and of Optimus
from the senate. Parthia was at this time torn by civil commotions, which rendered the conquests of Trajan all the easier.
In the spring of the following year, A. D. 115, he crossed the Tigris, took Ctesiphon and Seleuceia, and made Mesopotamia, Assyria, and Babylonia, Roman provinces.
After these conquests, he sailed down the Tigris to the Persian gulf and the Indian ocean; but during his absence there was a general revolt of the Parthians.
He immediately sent against them two of his generals, Maximus and Lusius, A. D. 116, the former of whom was defeated and slain by Chosroes, but the latter met with more success, and regained the cities of Nisibis, Edessa, and Seleuceia, as well as others which had revolted. Upon his return to Ctesiphon, Trajan appointed Parthamaspates king of Parthia, and then withdrew from the country to invade Arabia. Upon the death of Trajan, however, in the following year (A. D. 117), the Parthians expelled Parthanmaspates, and placed upon the throne their former king, Chosroes. But Hadrian, who had succeeded Trajan, was unwilling to engage in a war with the Parthians, and judged it more prudent to give up the conquests which Trajan had gained; he accordingly withdrew the Roman garrisons from Mesopotamia, Assyria, and Babylonia, and made the Euphrates, as before, the eastern boundary of the Roman empire.
The exact time of Chosroes' death is unknown; but during the remainder of his reign there was no war between the Parthians and the Romans, as Hadrian cultivated friendly relations with the former. (Dio Cass. ixviii. 17-33; Aurel. Vict. Caes.
100.13 ; Paus. 5.12.4
; Spartian, Hadr.